# File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 55
55:       def initialize(connection, logger, config = {})
56:         super(connection, logger)
57:         @config = config
58:         @async = config[:allow_concurrency]
59:         configure_connection
60:       end

    # File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 63
63:       def active?
64:         if @connection.respond_to?(:status)
65:           @connection.status == PGconn::CONNECTION_OK
66:         else
67:           @connection.query 'SELECT 1'
68:           true
69:         end
70:       # postgres-pr raises a NoMethodError when querying if no conn is available
71:       rescue PGError, NoMethodError
72:         false
73:       end

    # File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 51
51:       def adapter_name
52:         'PostgreSQL'
53:       end

     # File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 334
334:       def add_column(table_name, column_name, type, options = {})
335:         default = options[:default]
336:         notnull = options[:null] == false
337: 
338:         # Add the column.
339:         execute("ALTER TABLE #{table_name} ADD COLUMN #{column_name} #{type_to_sql(type, options[:limit])}")
340: 
341:         # Set optional default. If not null, update nulls to the new default.
342:         unless default.nil?
343:           change_column_default(table_name, column_name, default)
344:           if notnull
345:             execute("UPDATE #{table_name} SET #{column_name}='#{default}' WHERE #{column_name} IS NULL")
346:           end
347:         end
348: 
349:         if notnull
350:           execute("ALTER TABLE #{table_name} ALTER #{column_name} SET NOT NULL")
351:         end
352:       end

     # File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 258
258:       def default_sequence_name(table_name, pk = nil)
259:         default_pk, default_seq = pk_and_sequence_for(table_name)
260:         default_seq || "#{table_name}_#{pk || default_pk || 'id'}_seq"
261:       end

    # File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 84
84:       def disconnect!
85:         # Both postgres and postgres-pr respond to :close
86:         @connection.close rescue nil
87:       end

     # File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 89
 89:       def native_database_types
 90:         {
 91:           :primary_key => "serial primary key",
 92:           :string      => { :name => "character varying", :limit => 255 },
 93:           :text        => { :name => "text" },
 94:           :integer     => { :name => "integer" },
 95:           :float       => { :name => "float" },
 96:           :decimal     => { :name => "decimal" },
 97:           :datetime    => { :name => "timestamp" },
 98:           :timestamp   => { :name => "timestamp" },
 99:           :time        => { :name => "time" },
100:           :date        => { :name => "date" },
101:           :binary      => { :name => "bytea" },
102:           :boolean     => { :name => "boolean" }
103:         }
104:       end

     # File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 283
283:       def pk_and_sequence_for(table)
284:         # First try looking for a sequence with a dependency on the
285:         # given table's primary key.
286:         result = query("SELECT attr.attname, name.nspname, seq.relname\nFROM pg_class      seq,\npg_attribute  attr,\npg_depend     dep,\npg_namespace  name,\npg_constraint cons\nWHERE seq.oid           = dep.objid\nAND seq.relnamespace  = name.oid\nAND seq.relkind       = 'S'\nAND attr.attrelid     = dep.refobjid\nAND attr.attnum       = dep.refobjsubid\nAND attr.attrelid     = cons.conrelid\nAND attr.attnum       = cons.conkey[1]\nAND cons.contype      = 'p'\nAND dep.refobjid      = '\#{table}'::regclass\n", 'PK and serial sequence')[0]
287: 
288:         if result.nil? or result.empty?
289:           # If that fails, try parsing the primary key's default value.
290:           # Support the 7.x and 8.0 nextval('foo'::text) as well as
291:           # the 8.1+ nextval('foo'::regclass).
292:           # TODO: assumes sequence is in same schema as table.
293:           result = query("SELECT attr.attname, name.nspname, split_part(def.adsrc, '''', 2)\nFROM pg_class       t\nJOIN pg_namespace   name ON (t.relnamespace = name.oid)\nJOIN pg_attribute   attr ON (t.oid = attrelid)\nJOIN pg_attrdef     def  ON (adrelid = attrelid AND adnum = attnum)\nJOIN pg_constraint  cons ON (conrelid = adrelid AND adnum = conkey[1])\nWHERE t.oid = '\#{table}'::regclass\nAND cons.contype = 'p'\nAND def.adsrc ~* 'nextval'\n", 'PK and custom sequence')[0]
294:         end
295:         # check for existence of . in sequence name as in public.foo_sequence.  if it does not exist, return unqualified sequence
296:         # We cannot qualify unqualified sequences, as rails doesn't qualify any table access, using the search path
297:         [result.first, result.last]
298:       rescue
299:         nil
300:       end

     # File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 116
116:       def quote(value, column = nil)
117:         if value.kind_of?(String) && column && column.type == :binary
118:           "'#{escape_bytea(value)}'"
119:         else
120:           super
121:         end
122:       end

     # File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 124
124:       def quote_column_name(name)
125:         %("#{name}")
126:       end

     # File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 128
128:       def quoted_date(value)
129:         value.strftime("%Y-%m-%d %H:%M:%S.#{sprintf("%06d", value.usec)}")
130:       end

    # File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 76
76:       def reconnect!
77:         # TODO: postgres-pr doesn't have PGconn#reset.
78:         if @connection.respond_to?(:reset)
79:           @connection.reset
80:           configure_connection
81:         end
82:       end

     # File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 330
330:       def rename_table(name, new_name)
331:         execute "ALTER TABLE #{name} RENAME TO #{new_name}"
332:       end

     # File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 264
264:       def reset_pk_sequence!(table, pk = nil, sequence = nil)
265:         unless pk and sequence
266:           default_pk, default_sequence = pk_and_sequence_for(table)
267:           pk ||= default_pk
268:           sequence ||= default_sequence
269:         end
270:         if pk
271:           if sequence
272:             select_value "SELECT setval('\#{sequence}', (SELECT COALESCE(MAX(\#{pk})+(SELECT increment_by FROM \#{sequence}), (SELECT min_value FROM \#{sequence})) FROM \#{table}), false)\n", 'Reset sequence'
273:           else
274:             @logger.warn "#{table} has primary key #{pk} with no default sequence" if @logger
275:           end
276:         end
277:       end

     # File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 106
106:       def supports_migrations?
107:         true
108:       end

     # File vendor/rails/activerecord/lib/active_record/connection_adapters/postgresql_adapter.rb, line 110
110:       def table_alias_length
111:         63
112:       end